-
Question 1
Correct
-
A 68-year-old woman presents to her GP for a routine health check-up. She has a medical history of hypertension, which is managed with a daily dose of ACE inhibitor. During a screening DEXA scan, her pelvis and femur show T-scores of -2.6 and -2.9, respectively.
What results would you anticipate from her laboratory tests?Your Answer: Normal serum calcium, serum phosphate, ALP and PTH
Explanation:Osteoporosis is the diagnosis for this patient, as indicated by a T-score of less than -2.5 on their DEXA scan. Their lab results for serum calcium, serum phosphate, ALP, and PTH are all within normal ranges for osteoporosis.
Patients with osteomalacia typically have decreased serum calcium and serum phosphate levels, along with increased ALP and PTH levels.
Paget’s disease is characterized by an isolated increase in ALP, while the rest of the lab values are normal.
Hyperparathyroidism is indicated by increased PTH levels, with the specific lab values depending on whether the patient has primary or secondary hyperparathyroidism.
Primary hyperparathyroidism is characterized by raised PTH, calcium, and ALP levels, as increased bone resorption leads to high serum calcium and ALP levels. PTH also causes increased phosphate excretion by the kidneys, resulting in low serum phosphate levels.
Secondary hyperparathyroidism is indicated by raised PTH, phosphate, and ALP levels, typically seen in patients with chronic kidney disease. In this case, the kidneys cannot excrete phosphate, leading to increased serum phosphate levels, which in turn causes increased PTH secretion. PTH causes bone resorption, leading to high ALP levels. Chronic kidney disease also impairs vitamin D activation, resulting in hypocalcemia.
Lab Values for Bone Disorders
When it comes to bone disorders, certain lab values can provide important information about the condition. In cases of osteoporosis, calcium, phosphate, alkaline phosphatase (ALP), and parathyroid hormone (PTH) levels are typically normal. However, in osteomalacia, calcium and phosphate levels are decreased while ALP and PTH levels are increased. Primary hyperparathyroidism, which can lead to osteitis fibrosa cystica, is characterized by increased calcium and PTH levels but decreased phosphate levels. Chronic kidney disease can result in secondary hyperparathyroidism, which is marked by decreased calcium levels and increased phosphate and PTH levels. Paget’s disease, on the other hand, typically shows normal calcium and phosphate levels but increased ALP levels. Finally, osteopetrosis is associated with normal levels of calcium, phosphate, ALP, and PTH. By analyzing these lab values, healthcare professionals can better diagnose and treat bone disorders.
-
This question is part of the following fields:
- Musculoskeletal System And Skin
-
-
Question 2
Incorrect
-
A 57-year-old woman with metastatic breast cancer experiences severe groin pain upon getting out of bed due to an oestolytic deposit in the proximal femur. X-rays reveal an avulsed lesser trochanter. What muscle is the most probable cause?
Your Answer: Piriformis
Correct Answer: Psoas major
Explanation:The lesser trochanter is the insertion point for the psoas major, which contracts during the act of raising the trunk from a supine position. In cases where there are oestolytic lesions in the femur, the lesser trochanter may become avulsed.
The Psoas Muscle: Origin, Insertion, Innervation, and Action
The psoas muscle is a deep-seated muscle that originates from the transverse processes of the five lumbar vertebrae and the superficial part originates from T12 and the first four lumbar vertebrae. It inserts into the lesser trochanter of the femur and is innervated by the anterior rami of L1 to L3.
The main action of the psoas muscle is flexion and external rotation of the hip. When both sides of the muscle contract, it can raise the trunk from the supine position. The psoas muscle is an important muscle for maintaining proper posture and movement, and it is often targeted in exercises such as lunges and leg lifts.
-
This question is part of the following fields:
- Musculoskeletal System And Skin
-
-
Question 3
Correct
-
A 72-year-old man is having a carotid endarterectomy due to recurrent TIAs and the external carotid artery is visible. What is the initial branch of the external carotid artery?
Your Answer: The superior thyroid artery
Explanation:The Superior Thyroid Artery and its Branches
The superior thyroid artery is the initial branch of the external carotid artery. It descends downwards along the side of the pharynx before turning anteriorly to provide blood supply to the upper part of the thyroid gland. The external carotid artery has several branches, which are arranged in a descending order from inferior to superior. These branches include the superior thyroid, lingual, facial, occipital, posterior auricular, superficial temporal, and maxillary arteries.
The superior thyroid artery is responsible for supplying blood to the upper pole of the thyroid gland. It is one of the first branches of the external carotid artery and runs downwards along the side of the pharynx before turning anteriorly. The external carotid artery has several branches, which are arranged in a descending order from inferior to superior. These branches include the superior thyroid, lingual, facial, occipital, posterior auricular, superficial temporal, and maxillary arteries.
-
This question is part of the following fields:
- Clinical Sciences
-
-
Question 4
Correct
-
As it leaves the axilla, which muscle does the radial nerve pass over?
Your Answer: Teres major
Explanation:The triangular space serves as a pathway for the radial nerve to exit the axilla. Its upper boundary is defined by the teres major muscle, which has a close association with the radial nerve.
The Radial Nerve: Anatomy, Innervation, and Patterns of Damage
The radial nerve is a continuation of the posterior cord of the brachial plexus, with root values ranging from C5 to T1. It travels through the axilla, posterior to the axillary artery, and enters the arm between the brachial artery and the long head of triceps. From there, it spirals around the posterior surface of the humerus in the groove for the radial nerve before piercing the intermuscular septum and descending in front of the lateral epicondyle. At the lateral epicondyle, it divides into a superficial and deep terminal branch, with the deep branch crossing the supinator to become the posterior interosseous nerve.
The radial nerve innervates several muscles, including triceps, anconeus, brachioradialis, and extensor carpi radialis. The posterior interosseous branch innervates supinator, extensor carpi ulnaris, extensor digitorum, and other muscles. Denervation of these muscles can lead to weakness or paralysis, with effects ranging from minor effects on shoulder stability to loss of elbow extension and weakening of supination of prone hand and elbow flexion in mid prone position.
Damage to the radial nerve can result in wrist drop and sensory loss to a small area between the dorsal aspect of the 1st and 2nd metacarpals. Axillary damage can also cause paralysis of triceps. Understanding the anatomy, innervation, and patterns of damage of the radial nerve is important for diagnosing and treating conditions that affect this nerve.
-
This question is part of the following fields:
- Neurological System
-
-
Question 5
Incorrect
-
What is the molecule produced at the end of glycolysis that connects to the Kreb cycle?
Your Answer: Oxaloacetate
Correct Answer: Acetyl CoA
Explanation:The Process of Energy Production from Glucose
The process of producing energy from glucose involves several steps. The first step is glycolysis, where glucose is converted into fructose 1,6 bisphosphate and split into two 3-carbon particles. These particles are then converted into acetyl CoA, which provides the link with the Kreb cycle. The Kreb cycle, also known as the tricarboxylic acid cycle, is a process where organic acids are modified in a series of steps to produce NADH. Succinate and oxaloacetate are intermediates in the Kreb cycle.
The final step in the process is the electron transfer chain, which occurs inside mitochondria. The NADH generated during the Kreb cycle is used to produce energy in the form of adenosine triphosphate (ATP) by a series of redox reactions. This process is essential for the production of energy in the body, as ATP is the primary source of energy for cellular processes. By the process of energy production from glucose, we can better understand the importance of maintaining a healthy diet and lifestyle to ensure optimal energy production in the body.
-
This question is part of the following fields:
- Clinical Sciences
-
-
Question 6
Incorrect
-
Which one of the following statements relating to the pharmacology of warfarin is false?
Your Answer: Interferes with clotting factors 2,7,9 and 10
Correct Answer: Warfarin has a large volume of distribution
Explanation:To impair fibrin formation, warfarin impacts the carboxylation of glutamic acid residues in clotting factors 2, 7, 9, and 10. Factor 2 has the lengthiest half-life of around 60 hours, so it may take up to three days for warfarin to take full effect. Warfarin is protein-bound, resulting in a small distribution volume.
Understanding Warfarin: Mechanism of Action, Indications, Monitoring, Factors, and Side-Effects
Warfarin is an oral anticoagulant that has been widely used for many years to manage venous thromboembolism and reduce stroke risk in patients with atrial fibrillation. However, it has been largely replaced by direct oral anticoagulants (DOACs) due to their ease of use and lack of need for monitoring. Warfarin works by inhibiting epoxide reductase, which prevents the reduction of vitamin K to its active hydroquinone form. This, in turn, affects the carboxylation of clotting factor II, VII, IX, and X, as well as protein C.
Warfarin is indicated for patients with mechanical heart valves, with the target INR depending on the valve type and location. Mitral valves generally require a higher INR than aortic valves. It is also used as a second-line treatment after DOACs for venous thromboembolism and atrial fibrillation, with target INRs of 2.5 and 3.5 for recurrent cases. Patients taking warfarin are monitored using the INR, which may take several days to achieve a stable level. Loading regimes and computer software are often used to adjust the dose.
Factors that may potentiate warfarin include liver disease, P450 enzyme inhibitors, cranberry juice, drugs that displace warfarin from plasma albumin, and NSAIDs that inhibit platelet function. Warfarin may cause side-effects such as haemorrhage, teratogenic effects, skin necrosis, temporary procoagulant state, thrombosis, and purple toes.
In summary, understanding the mechanism of action, indications, monitoring, factors, and side-effects of warfarin is crucial for its safe and effective use in patients. While it has been largely replaced by DOACs, warfarin remains an important treatment option for certain patients.
-
This question is part of the following fields:
- Cardiovascular System
-
-
Question 7
Incorrect
-
Which one of the following is not a pathological response to extensive burns in elderly patients?
Your Answer: Increased haematocrit
Correct Answer: Absolute polycythaemia
Explanation:The primary pathological response is haemolysis.
Pathology of Burns
Extensive burns can cause various pathological changes in the body. The heat and microangiopathy can damage erythrocytes, leading to haemolysis. The loss of capillary membrane integrity can cause plasma leakage into the interstitial space, resulting in hypovolaemic shock. This shock can occur up to 48 hours after the injury and can cause a decrease in blood volume and an increase in haematocrit. Additionally, protein loss and secondary infections, such as Staphylococcus aureus, can occur. There is also a risk of acute peptic stress ulcers, known as Curling’s ulcers. Furthermore, full-thickness circumferential burns in an extremity can lead to compartment syndrome.
The healing process of burns depends on the severity of the burn. Superficial burns can heal through the migration of keratinocytes to form a new layer over the burn site. However, full-thickness burns can result in dermal scarring, which may require skin grafts to provide optimal coverage. It is important to understand the pathology of burns to provide appropriate treatment and prevent further complications.
-
This question is part of the following fields:
- Musculoskeletal System And Skin
-
-
Question 8
Correct
-
A 29-year-old male is admitted after a car accident. During examination, his heart rate is found to be 125 beats/min, and his blood pressure is 120/105 mmHg. Upon palpation, his abdomen is tense and tender. The diagnosis is hypovolemic shock. Which receptor stimulation has led to compensation for the blood loss?
Your Answer: Alpha 1 adrenergic
Explanation:Activation of alpha 1 adrenergic receptors leads to the contraction of smooth muscles. This causes vasoconstriction in the skin, gut, and kidney arterioles, increasing total peripheral resistance and mean arterial pressure. It also helps to improve perfusion of vital organs such as the brain, heart, and lungs during the fight or flight response.
On the other hand, activation of beta 2 adrenergic receptors results in the dilation of smooth muscles, such as bronchodilation. Activation of beta 3 adrenergic receptors enhances lipolysis in adipose tissue. Activation of alpha 2 adrenergic receptors inhibits the release of noradrenaline, providing negative feedback.
Activation of the muscarinic M2 acetylcholine receptor decreases heart rate, which could worsen compensation.
Adrenergic receptors are a type of G protein-coupled receptors that respond to the catecholamines epinephrine and norepinephrine. These receptors are primarily involved in the sympathetic nervous system. There are four types of adrenergic receptors: α1, α2, β1, and β2. Each receptor has a different potency order and primary action. The α1 receptor responds equally to norepinephrine and epinephrine, causing smooth muscle contraction. The α2 receptor has mixed effects and responds equally to both catecholamines. The β1 receptor responds equally to epinephrine and norepinephrine, causing cardiac muscle contraction. The β2 receptor responds much more strongly to epinephrine than norepinephrine, causing smooth muscle relaxation.
-
This question is part of the following fields:
- General Principles
-
-
Question 9
Correct
-
Mr. Johnson is a 72-year-old man who was diagnosed with chronic lymphocytic leukaemia (CLL) 18 months ago. His disease has been stable, however he has now presented with fatigue and splenomegaly. His blood results are shown below.
Hb 85 g/dL
WCC 41 x 109 cells/L
Plts 210 x 109 cells/L
MCV 88 fl
Haptoglobin 115 mg/dL (30-200 mg/dL)
Direct Coombs test Positive
What is the most likely diagnosis?Your Answer: Warm autoimmune haemolytic anaemia
Explanation:CLL is linked to warm autoimmune haemolytic anaemia.
Complications of Chronic Lymphocytic Leukaemia
Chronic lymphocytic leukaemia (CLL) is a type of cancer that affects the blood and bone marrow. It can lead to various complications, including anaemia, hypogammaglobulinaemia, and warm autoimmune haemolytic anaemia. Patients with CLL may also experience recurrent infections due to their weakened immune system. However, one of the most severe complications of CLL is Richter’s transformation.
Richter’s transformation occurs when CLL cells transform into a high-grade, fast-growing non-Hodgkin’s lymphoma. This transformation can happen when the leukaemia cells enter the lymph nodes. Patients with Richter’s transformation often become unwell very suddenly and may experience symptoms such as lymph node swelling, fever without infection, weight loss, night sweats, nausea, and abdominal pain.
It is essential for patients with CLL to be aware of the potential complications and to seek medical attention if they experience any concerning symptoms. Regular check-ups and monitoring can also help detect any changes in the condition early on, allowing for prompt treatment and management.
-
This question is part of the following fields:
- Haematology And Oncology
-
-
Question 10
Incorrect
-
Which of the following statements about the ankle joint is false?
Your Answer: Eversion of the foot occurs at the sub talar joint
Correct Answer: The sural nerve lies medial to the Achilles tendon at its point of insertion
Explanation:The distal fibula is located in front of the sural nerve. Subtalar movements involve inversion and eversion. When passing behind the medial malleolus from front to back, the structures include the tibialis posterior, flexor digitorum longus, posterior tibial vein, posterior tibial artery, nerve, and flexor hallucis longus.
Anatomy of the Ankle Joint
The ankle joint is a type of synovial joint that is made up of the tibia and fibula superiorly and the talus inferiorly. It is supported by several ligaments, including the deltoid ligament, lateral collateral ligament, and talofibular ligaments. The calcaneofibular ligament is separate from the fibrous capsule of the joint, while the two talofibular ligaments are fused with it. The syndesmosis is composed of the antero-inferior tibiofibular ligament, postero-inferior tibiofibular ligament, inferior transverse tibiofibular ligament, and interosseous ligament.
The ankle joint allows for plantar flexion and dorsiflexion movements, with a range of 55 and 35 degrees, respectively. Inversion and eversion movements occur at the level of the sub talar joint. The ankle joint is innervated by branches of the deep peroneal and tibial nerves.
Reference:
Golano P et al. Anatomy of the ankle ligaments: a pictorial essay. Knee Surg Sports Traumatol Arthrosc. 2010 May;18(5):557-69. -
This question is part of the following fields:
- Musculoskeletal System And Skin
-
-
Question 11
Incorrect
-
A 60-year-old man comes to the dermatology clinic complaining of a rash. During the examination, the doctor observes a linear rash on the lateral thigh of the left leg. The patient reports having undergone a left hip replacement surgery recently, and the rash has developed over the surgical scar.
What skin condition is most likely responsible for this presentation?Your Answer: Atopic dermatitis
Correct Answer: Psoriasis
Explanation:The Koebner Phenomenon: Skin Lesions at the Site of Injury
The Koebner phenomenon refers to the occurrence of skin lesions at the site of injury. This phenomenon is commonly observed in various skin conditions such as psoriasis, vitiligo, warts, lichen planus, lichen sclerosus, and molluscum contagiosum. In other words, if a person with any of these skin conditions experiences trauma or injury to their skin, they may develop new lesions in the affected area.
This phenomenon is named after Heinrich Koebner, a German dermatologist who first described it in 1876. The exact mechanism behind the Koebner phenomenon is not fully understood, but it is believed to be related to the immune system’s response to injury. In some cases, the injury may trigger an autoimmune response, leading to the development of new lesions.
The Koebner phenomenon can be a frustrating and challenging aspect of managing skin conditions. It is important for individuals with these conditions to take precautions to avoid injury to their skin, such as wearing protective clothing or avoiding activities that may cause trauma. Additionally, prompt treatment of any new lesions that develop can help prevent further spread of the condition.
-
This question is part of the following fields:
- Musculoskeletal System And Skin
-
-
Question 12
Incorrect
-
A 78-year-old woman has presented with dyspnea. During cardiovascular examination, a faint murmur is detected in the mitral area. If the diagnosis is mitral stenosis, what is the most probable factor that would increase the loudness and clarity of the murmur during auscultation?
Your Answer: Ask the patient to lean over on their right side
Correct Answer: Ask the patient to breathe out
Explanation:To accentuate the sound of a left-sided murmur consistent with mitral stenosis during a cardiovascular examination, the patient should be asked to exhale. Conversely, a right-sided murmur is louder during inspiration. Listening in the left lateral position while the patient is lying down can also emphasize a mitral stenosis. To identify a mitral regurgitation murmur, listening in the axilla is helpful as it radiates. Diastolic murmurs can be heard better with a position change, while systolic murmurs tend to radiate and can be distinguished by listening in different anatomical landmarks. For example, an aortic stenosis may radiate to the carotids, while an aortic regurgitation may be heard better with the patient leaning forward.
Understanding Mitral Stenosis
Mitral stenosis is a condition where the mitral valve, which controls blood flow from the left atrium to the left ventricle, becomes obstructed. This leads to an increase in pressure within the left atrium, pulmonary vasculature, and right side of the heart. The most common cause of mitral stenosis is rheumatic fever, but it can also be caused by other rare conditions such as mucopolysaccharidoses, carcinoid, and endocardial fibroelastosis.
Symptoms of mitral stenosis include dyspnea, hemoptysis, a mid-late diastolic murmur, a loud S1, and a low volume pulse. Severe cases may also present with an increased length of murmur and a closer opening snap to S2. Chest x-rays may show left atrial enlargement, while echocardiography can confirm a cross-sectional area of less than 1 sq cm for a tight mitral stenosis.
Management of mitral stenosis depends on the severity of the condition. Asymptomatic patients are monitored with regular echocardiograms, while symptomatic patients may undergo percutaneous mitral balloon valvotomy or mitral valve surgery. Patients with associated atrial fibrillation require anticoagulation, with warfarin currently recommended for moderate/severe cases. However, there is an emerging consensus that direct-acting anticoagulants may be suitable for mild cases with atrial fibrillation.
Overall, understanding mitral stenosis is important for proper diagnosis and management of this condition.
-
This question is part of the following fields:
- Cardiovascular System
-
-
Question 13
Correct
-
A 27-year-old male has an accident at work where he is injured by a loose piece of glass. The glass cuts his skin and damages the tendons of one of the muscles in his hand. Consequently, he cannot flex the distal interphalangeal joint of his ring finger. However, he can still flex the proximal interphalangeal joint (PIP) and the metacarpophalangeal (MCP) joint of the same finger. None of his other fingers are impacted.
Which muscle is likely to have been affected?Your Answer: Flexor digitorum profundus
Explanation:The flexor digitorum profundus muscle is primarily responsible for flexing the distal interphalangeal joint. It is located deep to the flexor digitorum superficialis muscle and is specific to each digit. The flexor digitorum superficialis muscle, on the other hand, flexes the metacarpophalangeal and proximal interphalangeal joints. The flexor carpi ulnaris muscle is responsible for flexing and adducting the wrist, while the flexor pollicis longus muscle flexes the thumb. It is important to note that the flexor digitorum superficialis muscle must be intact for its function to remain present.
The forearm flexor muscles include the flexor carpi radialis, palmaris longus, flexor carpi ulnaris, flexor digitorum superficialis, and flexor digitorum profundus. These muscles originate from the common flexor origin and surrounding fascia, and are innervated by the median and ulnar nerves. Their actions include flexion and abduction of the carpus, wrist flexion, adduction of the carpus, and flexion of the metacarpophalangeal and interphalangeal joints.
-
This question is part of the following fields:
- Musculoskeletal System And Skin
-
-
Question 14
Incorrect
-
You are interviewing a patient who has recently been admitted to the acute psychiatric ward. When talking, he is difficult to interrupt. While describing his reaction to the death of his grandfather, he says, The police asked me to identify his body. Ha ha ha! I was shocked to see him lying there! Ha ha ha! What is the best description of this mental state?
Your Answer: Blunting of affect
Correct Answer: Incongruity of affect
Explanation:Schizophrenia Symptoms: Incongruity of Affect and Perseveration
Incongruity of affect is a symptom commonly seen in individuals with schizophrenia. It refers to the unpredictable and contradictory emotional response to events. For instance, an insignificant event may trigger a severe emotional reaction, while a significant event may produce no response or an opposite response. This symptom can be observed when a person laughs while recalling a traumatic event.
It is important to differentiate incongruity of affect from a slight smile that may occur in an anxious or shocked person following a traumatic event. Incongruity of affect is a more severe and persistent symptom that is characteristic of schizophrenia.
Another symptom of schizophrenia is perseveration, which refers to the inability to stop an action or thought. For example, if someone is asked to tap on a table once, they may continue tapping even after the task is completed. This symptom can be frustrating for the individual and may interfere with their daily activities.
In summary, incongruity of affect and perseveration are two symptoms commonly seen in individuals with schizophrenia. These symptoms can significantly impact their daily lives and require appropriate treatment and management.
-
This question is part of the following fields:
- Psychiatry
-
-
Question 15
Incorrect
-
A 36-year-old man is brought to the Emergency Department in an ambulance after being found unconscious by a friend. Shortly after arriving at the hospital, he becomes tachycardic, hypotensive, and stops breathing. The medical team suspects shock and examines him. What could be a potential cause of obstructive shock resulting from interference in ventricular filling?
Your Answer: Pulmonary embolism
Correct Answer: Tension pneumothorax
Explanation:Shock can be caused by various factors, but only tension pneumothorax affects ventricular filling. Distributive shock, such as anaphylactic shock, hypovolaemic shock caused by chemical burns, and cardiogenic shock resulting from myocardial infarction are other examples. Obstructive shock caused by pulmonary embolism interferes with ventricular emptying, not filling.
Shock is a condition where there is not enough blood flow to the tissues. There are five main types of shock: septic, haemorrhagic, neurogenic, cardiogenic, and anaphylactic. Septic shock is caused by an infection that triggers a particular response in the body. Haemorrhagic shock is caused by blood loss, and there are four classes of haemorrhagic shock based on the amount of blood loss and associated symptoms. Neurogenic shock occurs when there is a disruption in the autonomic nervous system, leading to decreased vascular resistance and decreased cardiac output. Cardiogenic shock is caused by heart disease or direct myocardial trauma. Anaphylactic shock is a severe, life-threatening allergic reaction. Adrenaline is the most important drug in treating anaphylaxis and should be given as soon as possible.
-
This question is part of the following fields:
- Gastrointestinal System
-
-
Question 16
Correct
-
What is the highest level of evidence in the hierarchy of evidence based medicine?
Your Answer: A well-conducted meta-analysis of randomised controlled trials
Explanation:The Hierarchy of Evidence in Healthcare
In healthcare, evidence-based practice is crucial in making informed decisions about patient care. The hierarchy of evidence is a framework used to determine the strength and reliability of research studies. At the top of the hierarchy is a meta-analysis, which combines data from multiple studies to provide the most comprehensive and reliable evidence. Randomised controlled trials follow, which are considered the gold standard in clinical research. Cohort studies and case-control studies are next in the hierarchy, followed by case series. At the bottom of the hierarchy is expert opinion, which is based on the experience and knowledge of healthcare professionals.
It is important to note that an evidence-based guideline is not included in the hierarchy of evidence, as it relies on the hierarchy to determine the strength of the evidence used to create the guideline. By following the hierarchy of evidence, healthcare professionals can make informed decisions about patient care based on the most reliable and trustworthy evidence available.
-
This question is part of the following fields:
- Clinical Sciences
-
-
Question 17
Correct
-
A 49-year-old male has sustained a facial burn at work. During the morning ward round, it is observed in the surgeon's notes that the facial artery has good arterial blood supply, leading to hope for satisfactory healing. What is the name of the major artery that the facial artery branches off from?
Your Answer: External carotid artery
Explanation:The facial artery is the primary source of blood supply to the face, originating from the external carotid artery after the lingual artery. It follows a winding path and terminates as the angular artery at the inner corner of the eye.
The internal carotid artery provides blood to the front and middle parts of the brain, while the vertebral artery, a branch of the subclavian artery, supplies the spinal cord, cerebellum, and back part of the brain. The brachiocephalic artery supplies the right side of the head and arm, giving rise to the subclavian and common carotid arteries on the right side.
Anatomy of the External Carotid Artery
The external carotid artery begins on the side of the pharynx and runs in front of the internal carotid artery, behind the posterior belly of digastric and stylohyoid muscles. It is covered by sternocleidomastoid muscle and passed by hypoglossal nerves, lingual and facial veins. The artery then enters the parotid gland and divides into its terminal branches within the gland.
To locate the external carotid artery, an imaginary line can be drawn from the bifurcation of the common carotid artery behind the angle of the jaw to a point in front of the tragus of the ear.
The external carotid artery has six branches, with three in front, two behind, and one deep. The three branches in front are the superior thyroid, lingual, and facial arteries. The two branches behind are the occipital and posterior auricular arteries. The deep branch is the ascending pharyngeal artery. The external carotid artery terminates by dividing into the superficial temporal and maxillary arteries within the parotid gland.
-
This question is part of the following fields:
- Cardiovascular System
-
-
Question 18
Correct
-
A 67-year-old man patient with a history of recurrent renal stones is referred to an endocrinologist for further investigations. The doctor performs a series of investigations, which includes the following results:
Calcium 2.9 mmol/L (2.1-2.6)
Phosphate 0.7 mmol/L (0.8-1.4)
Magnesium 0.8 mmol/L (0.7-1.0)
Thyroid stimulating hormone (TSH) 3.9 mU/L (0.5-5.5)
Free thyroxine (T4) 17.5 pmol/L (9.0 - 18)
Amylase 110 U/L (70 - 300)
Uric acid 0.42 mmol/L (0.18 - 0.48)
Creatine kinase 130 U/L (35 - 250)
What is the most likely cause of this abnormality in the patient's test results?Your Answer: Parathyroid hormone (PTH)
Explanation:The regulation of calcium metabolism is mainly controlled by PTH and calcitriol. The patient is exhibiting symptoms of hyperparathyroidism, which is caused by excessive levels of parathyroid hormone leading to high serum calcium levels. This can result in recurrent renal stones, as well as other symptoms such as abdominal pain, fatigue, and confusion.
Antidiuretic hormone, which promotes water retention in the body, does not directly affect calcium metabolism and is therefore not the correct answer.
An excess of calcitriol would cause abnormally low levels of serum calcium, which does not match the clinical presentation in this case.
Gonadotropin-releasing hormone stimulates the secretion of LH and FSH from the anterior pituitary gland and is not expected to affect calcium and phosphate levels.
Hormones Controlling Calcium Metabolism
Calcium metabolism is primarily controlled by two hormones, parathyroid hormone (PTH) and 1,25-dihydroxycholecalciferol (calcitriol). Other hormones such as calcitonin, thyroxine, and growth hormone also play a role. PTH increases plasma calcium levels and decreases plasma phosphate levels. It also increases renal tubular reabsorption of calcium, osteoclastic activity, and renal conversion of 25-hydroxycholecalciferol to 1,25-dihydroxycholecalciferol. On the other hand, 1,25-dihydroxycholecalciferol increases plasma calcium and plasma phosphate levels, renal tubular reabsorption and gut absorption of calcium, osteoclastic activity, and renal phosphate reabsorption. It is important to note that osteoclastic activity is increased indirectly by PTH as osteoclasts do not have PTH receptors. Understanding the actions of these hormones is crucial in maintaining proper calcium metabolism in the body.
-
This question is part of the following fields:
- General Principles
-
-
Question 19
Incorrect
-
What is the carrier rate of cystic fibrosis in the United Kingdom?
Your Answer: 1 in 100
Correct Answer: 1 in 25
Explanation:Understanding Cystic Fibrosis
Cystic fibrosis is a genetic disorder that causes thickened secretions in the lungs and pancreas. It is an autosomal recessive condition that occurs due to a defect in the cystic fibrosis transmembrane conductance regulator gene (CFTR), which regulates a chloride channel. In the UK, 80% of CF cases are caused by delta F508 on chromosome 7, and the carrier rate is approximately 1 in 25.
CF patients are at risk of colonization by certain organisms, including Staphylococcus aureus, Pseudomonas aeruginosa, Burkholderia cepacia (previously known as Pseudomonas cepacia), and Aspergillus. These organisms can cause infections and exacerbate symptoms in CF patients. It is important for healthcare providers to monitor and manage these infections to prevent further complications.
Overall, understanding cystic fibrosis and its associated risks can help healthcare providers provide better care for patients with this condition.
-
This question is part of the following fields:
- Respiratory System
-
-
Question 20
Incorrect
-
A 28-year-old primigravida, at 8 weeks gestation presents for her prenatal check-up. She reports taking a daily vitamin and denies any use of tobacco, alcohol, or illicit drugs. On examination, her blood pressure is 118/66 mmHg and pulse is 78/min. Bimanual examination reveals a 10-week-sized non-tender uterus with no adnexal masses or tenderness. Ultrasound shows two 8-week intrauterine gestations with normal heartbeats, a single placenta, and no dividing intertwine membrane.
What is the most likely diagnosis for this patient?Your Answer: Monochorionic diamniotic twins
Correct Answer: Monochorionic monoamniotic twins
Explanation:Twin Pregnancies: Incidence, Types, and Complications
Twin pregnancies occur in approximately 1 out of 105 pregnancies, with the majority being dizygotic or non-identical twins. Monozygotic or identical twins, on the other hand, develop from a single ovum that has divided to form two embryos. However, monoamniotic monozygotic twins are associated with increased risks of spontaneous miscarriage, perinatal mortality rate, malformations, intrauterine growth restriction, prematurity, and twin-to-twin transfusions. The incidence of dizygotic twins is increasing due to infertility treatment, and predisposing factors include previous twins, family history, increasing maternal age, multigravida, induced ovulation, in-vitro fertilisation, and race, particularly Afro-Caribbean.
Antenatal complications of twin pregnancies include polyhydramnios, pregnancy-induced hypertension, anaemia, and antepartum haemorrhage. Fetal complications include perinatal mortality, prematurity, light-for-date babies, and malformations, especially in monozygotic twins. Labour complications may also arise, such as postpartum haemorrhage, malpresentation, cord prolapse, and entanglement.
Management of twin pregnancies involves rest, ultrasound for diagnosis and monthly checks, additional iron and folate, more antenatal care, and precautions during labour, such as having two obstetricians present. Most twins deliver by 38 weeks, and if longer, most are induced at 38-40 weeks. Overall, twin pregnancies require close monitoring and management to ensure the best possible outcomes for both mother and babies.
-
This question is part of the following fields:
- Reproductive System
-
00
Correct
00
Incorrect
00
:
00
:
00
Session Time
00
:
00
Average Question Time (
Secs)